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LM2940C: For Negative voltage

Hiroshi Doi35
Expert 2845 points
Part Number: LM2940C
Other Parts Discussed in Thread: LM2990, LM79, LM337-N

Hi all,

Can LM2940C be used for Negative voltage?

Because LM2990 is too much High-cost. My customer rejected it.

If you have the idea for negative voltage use, please teach me the circuit.

  • 0
    TI__Genius 10200 points

    Hi,

    The LM2940C was designed as a positive LDO voltage regulator with a recommended operating input voltage of 6 V to 26 V. To ensure consistent and reliable operation, this device should not be used with a negative input voltage.

    The LM337-N and the LM79 are some examples of TI's negative voltage regulators that are cheaper than the LM2990 and support at least 1 A load current. If you provide more information about your customer's application I will be able to make a more specific recommendation. You can also parametric search TI's LDO and linear regulator portfolio based on your customer's requirements here:

    http://www.ti.com/power-management/linear-regulators-ldo/products.html

    Thanks,

    Gerard

  • 0 in reply to Gerard Copeland
    Expert 2845 points

    Hi,

    Thank you.

    But they need "LDO".

    Your suggestion is not LDO.

    They accepted LM2940C price.

    So I need the reason why same internal component LM2990 is much higher price.

    Can you assert that the LM2940C sells 100 times more quantity than LM2990?

    If so, I can explain it to the customer.

  • 0 in reply to Hiroshi Doi35
    TI__Genius 10200 points
    Hi,

    The approximate 1ku price listed for these devices on the TI website is meant to provide an idea of the cost, but it is not a good indicator of the final price once an order is made. Although I cannot provide exact sales numbers, positive LDOs and linear regulators in general sell much larger volumes and have a much larger market supply than negative LDOs and linear regulators. This results in lower competitive pricing for positive LDOs compared to negative LDOs that have similar specs and performance metrics.

    Thanks,
    Gerard Copeland
  • 0 in reply to Gerard Copeland
    Expert 2845 points

    Thanks

    I Thinks Resolved